1. Technical Field
The present invention relates to a gas supply system and gas supply method for supplying gas to a body cavity of a patient to be operated, such as an abdominal cavity of a luminal cavity thereof, at two different predetermined pressure values.
2. Related Art
In recent years, laparoscopic surgeries have been practiced extensively. Under such laparoscopic surgeries, there are many probabilities where curative treatment is executed without opening an abdominal cavity for the purpose of treating a patient with minimally invasive capability.
Such laparoscopic surgeries have been executed in a way wherein a first trocar, through which, for instance, a rigidscope for observation is guided to a body cavity of the patient, and a second trocar, through which a treatment tool for executing curative treatment is guided to a site to be treated, are inserted to an abdominal portion of the patient.
Under such a laparoscopic surgery, with a view to ensuring a visual field of the rigidscope and ensuring an area for manipulating the treatment tool, an abdominal insufflation device has been used for supplying carbon dioxide gas (hereinafter also referred to as CO2) as abdominal cavity gas to the abdominal cavity of the patient.
Further, various proposals have heretofore been undertaken in gas supply apparatuses such as an abdominal insufflation device that supplies carbon dioxide gas to the abdominal cavity.
For instance, Japanese Patent Provisional Publication No. 2000-139830 discloses a gas supply apparatus arranged to control a gas flow rate such that under situations where the gas flow rate is less than the set value, an electropneumatic proportional valve (or also referred to as an electromagnetic proportional valve), serving as a pressure regulator means, is supplied with a control signal to cause an outlet pressure to increase so as to allow an internal pressure of a living body to lie at the set value.
Further, Japanese Patent Provisional Publication No. 8-256972 discloses an abdominal insufflation device that has a structure in which a plurality of delivery conduit switching units (electromagnetic valves), which switches communicating states of gas delivery members extending from a gas supply source to an insertion tool for an abdominal cavity, are unitarily assembled with a manifold valve for thereby achieving a miniaturization of flow rate control units.
In the meanwhile, a luminal cavity, such as the stomach and large intestine or the like, has been diagnosed and treated using a flexiblescope, equipped with an elongated and flexible inserter adapted to be inserted into the luminal cavity, and a treatment tool, inserted through a forceps channel of the flexiblescope and protruding from a channel opening at a distal end of an inserted portion, for executing curative treatment.
When executing medical procedures, such as diagnosis and treatment of the luminal cavity such as the stomach and large intestine or the like, on the patient under observation with the endoscope, probabilities occur where the luminal cavity is supplied with gas, such as air as “luminal cavity gas”, for the purpose of enhancing the visible field of the flexiblescope and enhancing the area for manipulating the treatment tool. Under such probabilities, although there are many cases where air, to be supplied to the luminal cavity, is delivered to the luminal cavity through the flexiblescope by a gas supply pump, it may be possible to use the above-described carbon dioxide gas.
Recently, new attempts have been undertaken where the laparoscopic surgeries are executed inserting a rigidscope to an abdominal cavity and inserting a flexiblescope to a luminal cavity while permitting both the endoscopes to be utilized for specifying a site for treatment. Even in such attempts, it has been probable that gas, such as air, for the luminal cavity is delivered to the luminal cavity through the flexiblescope inserted to the luminal cavity for distending the same.
However, in such cases, if air is delivered to the luminal cavity as described above, air is hard to be absorbed by the living body and, so, there are fears in that the luminal cavity remains under a distended state. For this reason, it has been contemplated to use an endoscope CO2 regulator (hereinafter referred to as ECR) by which gas such as, for instance, carbon dioxide gas (CO2) which can be easily absorbed by the living body, is supplied to the luminal cavity such as the large intestine or the like.
However, in cases where the related art endoscopic surgery system, for executing surgical operation under the endoscope, is structured to incorporate the ECR, the endoscopic surgery system needs a set of abdominal insufflation unit and a CO2 container and a set of the ECR and the CO2 container. This results in issues with the occurrence of troublesome preparation and inefficiency in space.
Further, abdominal cavity delivery gas and luminal cavity delivery gas differ in pressure from each other and, hence, carbon dioxide gas needs to be supplied to the abdominal cavity and luminal cavity at appropriate delivery pressures, respectively. Furthermore, since the ECR is designed to have a structure that is suitable for normal endoscopic inspection, that is, a structure in which carbon dioxide gas is supplied through the flexiblescope at a gas pressure suited only for the luminal cavity such as the large intestine, it becomes difficult sometimes for carbon dioxide gas to be adequately supplied because of an influence of an abdominal cavity pressure under the laparoscope.